![]() ![]() ![]() Compared with CD138, which disappears rapidly ex vivo, the expression of CD319 is considerably more stable. It is also expressed on malignant plasma cells in multiple myeloma. This antigen is expressed at high levels on normal human plasma cells. Īnother important surface antigen is CD319 (SLAMF7). ![]() The surface antigen CD138 (syndecan-1) is expressed at high levels. In humans, CD27 is a good marker for plasma cells naïve B cells are CD27−, memory B-cells are CD27+ and plasma cells are CD27++. Instead, plasma cells are identified through flow cytometry by their additional expression of CD138, CD78, and the Interleukin-6 receptor. Terminally differentiated plasma cells express relatively few surface antigens, and do not express common pan-B cell markers, such as CD19 and CD20. ![]() Other organelles in a plasma cell include ribosomes, lysosomes, mitochondria, and the plasma membrane. Abundant rough endoplasmic reticulum combined with a well-developed Golgi apparatus makes plasma cells well-suited for secreting immunoglobulins. Their cytoplasm also contains a pale zone that on electron microscopy contains an extensive Golgi apparatus and centrioles ( EM picture). They have basophilic cytoplasm and an eccentric nucleus with heterochromatin in a characteristic cartwheel or clock face arrangement. Plasma cells are large lymphocytes with abundant cytoplasm and a characteristic appearance on light microscopy. Structure Plasma cells with Dutcher and Russell bodies ( H&E stain, 100×, oil) B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell. These antibodies are transported from the plasma cells by the blood plasma and the lymphatic system to the site of the target antigen (foreign substance), where they initiate its neutralization or destruction. After inoculating rabbits with a human peptide associated with breast cancer, the researchers selected the animal with the best response, collected RNA from its white blood cells and sequenced transcripts coding for antibody chains.Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B lymphocytes and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens. To get around this problem, the researchers created a specialized reference database using next-generation sequencing. Because immune systems shuffle portions of the genes to produce a dizzying assortment of antibodies, however, these genes are not accurately represented in the reference databases. Reference databases based on gene collections can predict which fragments are likely to be produced by a particular protein digested by a particular enzyme and so identify proteins in the sample. A typical proteomics analysis involves enzymatically digesting collected proteins into peptide fragments and then characterizing them by mass spectrometry. However, analyzing the sequences of these proteins is more challenging. Purifying high-affinity antibodies produced in an inoculated mouse or rabbit is straightforward-these bind most tightly to an antigen and can readily be captured. ![]()
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